Method for allylating and vinylating aryl, heteroaryl, alkyl, and alkene halogenides using transition metal catalysis

ABSTRACT

What is described is a process for preparing organic compounds of the general formula (I)
 
R—R′  (I)
 
by converting a corresponding compound of the general formula (II)
 
R—X  (II)
 
in which
         X is fluorine, chlorine, bromine or iodine to an organomagnesium compound of the general formula (III)
 
[M + ] n [R m MgX k Y 1 ]  (III)
 
wherein compounds of the formula (III) are reacted with a compound of the general formula (IV)
       

                         
characterized in that the reaction of (III) with (IV) is performed in the presence of
         a) catalytic amounts of an iron compound, based on the compound of the general formula (II), and optionally in the presence of   b) a nitrogen-, oxygen- and/or phosphorus-containing additive in a catalytic or stoichiometric amount, based on the compound of the general formula (II).

The invention provides a process for preparing functionalized aryl,heteroaryl, alkenyl or alkyl compounds, by a transition metal-catalyzedcross-coupling reaction of an optionally substituted aryl, heteroaryl,alkenyl or alkylmagnesium compound with an optionally substituted allylcarboxylate, allyl carbonate, vinyl carboxylate or vinyl carbonate,wherein the formation of the organomagnesium compound from a halide canoptionally proceed in situ, in parallel to the coupling reaction.

Transition metal-catalyzed cross-couplings are some of the mostimportant synthetic tools in modern organic chemistry. The majority ofthe known cross-coupling reactions use palladium or nickel complexes astransition metal catalysts; in the case of coupling of allylic esters ascoupling components with organomagnesium compounds, copper complexes areregularly the catalyst of choice (for example Karlström et al., Synlett2001, 923), the prototype of which is the Kochi catalyst Li₂CuCl₄(Tamura et al., Synthesis 1971, 303). The very rare literaturedescriptions of the coupling of vinyl esters with organomagnesiumcompounds involve exclusively nickel catalysis (for example Wenkert etal., J. Am Chem. Soc. 1979, 101, 2246 and J. Org. Chem. 1984, 49, 4894).Usually, in these couplings, organic ligands in the form of phosphinesor N-heterocyclic carbenes are used, in order to achieve acceptablereactivity of the catalyst system. For economic (high palladium pricesand high volatility of the palladium prices, costly ligands which arefrequently unrecoverable) and toxicological reasons (high toxicity ofnickel compounds and microbicidal action of copper ions in treatmentplants), the use of these catalysts has distinct disadvantages. It wouldtherefore be desirable to be able to use, for this reaction type,catalysts based on less expensive, readily available and nontoxicmetals, if at all possible without expensive ligands which are difficultto prepare.

Under particular reaction conditions, iron compounds and also cobaltcompounds also have activity as catalysts in cross-coupling reactions.Especially compounds of iron are available at very favorable prices inits capacity as a base metal, and are of no concern in terms oftoxicology and wastewater legislation. Therefore, these compounds arepreferable as catalyst systems to palladium, which is expensive, nickel,which is toxic and harmful to the environment, and copper, which isharmful to the environment.

As early as the early 1970s, it was shown that iron salts can catalyzethe cross-coupling of vinyl halides with alkyl Grignard compounds (Kochiet al., J. Am. Chem. Soc. 1971, 1487). Due to a small range ofapplication, this reaction found only very limited use over the next 30years, until Knochel, Fürstner, Cahiez and Nakamura, since the start ofthe decade, succeeded in applying iron-catalyzed cross-couplings to awider range of substrates with the aid of nitrogen-containing addition,for example N-methylpyrrolidone or N,N,N′,N′-tetramethylethylenediamine(TMEDA) (for example Fürstner et al., Angew. Chem. Int. Ed. 2002, 41,609; Nakamura et al., J. Am, Chem. Soc. 2004, 3686; Knochel et al.,Synlett 2001, 1901; Cahiez et al., Angew. Chem. Int. Ed. 2007, 4364).These reactions are notable for particularly mild reaction conditions(−20° C. to +35° C.), high functional group compatibility (for examplemethyl esters, amines) and short reaction times (generally less than twohours). These reactions are also of particular interest for industrialapplication in that they generally do not require any expensive andsensitive phosphine or carbene ligands, as is frequently the case withnickel and palladium, especially when inexpensive chlorides rather thanbromides or iodides are to serve as coupling partners.

A common feature of all these reactions is that they couple a Grignardcompound to an alkyl, alkenyl or aryl halide, while it has not beenpossible to date to couple the widespread structural motif of the allylfunction with these inexpensive and environmentally friendly catalysts.This appears to be at least partly because of the competing Kharaschreaction, which leads to the decomposition of the Grignard compound (cf.Fürstner et al., Angew. Chem. Int. Ed. 2002, 41, 609).

It was therefore an object of the present invention to find a processfor preparing allyl and vinyl derivatives by cross-coupling, in whichinexpensive and environmentally friendly catalysts can be used in orderto couple readily available allyl and vinyl derivatives to aryl,heteroaryl, alkyl and alkenyl halides.

This object is achieved by the present invention by provision of aprocess which couples organomagnesium compounds derived from aryl,heteroaryl, alkyl and alkenyl halides, which can optionally be preparedin the presence of the allylic or vinylic coupling component, undercatalysis by iron complexes, with allyl and vinyl carboxylates and allyland vinyl carbonates, while maintaining the typical gentle conditions ofiron catalysis. This allows the substrate range of the iron-catalyzedcoupling to be widened considerably, since vinyl esters are obtainablein a very simple manner from aldehydes and ketones by enolization andacylation, and allyl esters from allyl alcohols.

The invention therefore provides a process for preparing organiccompounds of the general formula (I)R—R′  (I)

-   -   in which    -   R is an optionally mono- or polysubstituted aryl, heteroaryl,        alkenyl or alkyl radical, and    -   R′ is a vinyl or alkyl radical of the general formula II(a) or        II(b)

-   -   where j is 0, 1, 2 or 3 and        -   q are identical or different groups other than H, by            converting a compound of the general formula (II)            R—X  (II)    -   in which    -   X is fluorine, chlorine, bromine or iodine, and    -   R is as defined for formula (I),    -   to an organomagnesium compound of the general formula (III)        [M⁺]_(n)[R_(m)MgX_(k)Y₁]  (III)    -   in which    -   R is as defined for formula (I),    -   X is an anion as defined for formula (II),    -   M is a monovalent cation,    -   Y is a monovalent anion,    -   n is either 0 or n is 1, 2, 3, 4,    -   m is 1, 2, 3, 4, 5 or 6,    -   k is 0, 1, 2, 3 or 4,    -   l is 0, 1, 2, 3 or 4,    -   and, at the same time, the following relationship applies:        n+2=m+k+1,    -   followed by reaction of the compound (III) with a compound of        the general formula (IV)

-   -   in which    -   R′ is as defined for formula (I) and is bonded to the oxygen        atom in the allyl or vinyl position and    -   R″ is an optionally substituted alkyl, alkoxy, aryl, aryloxy,        heteroaryl or heteroaryloxy group,    -   characterized in that the reaction of (III) with (IV), and        optionally also the step from (II) to (III), is performed in the        presence of    -   a) catalytic amounts of an iron compound, based on the compound        of the general formula (II),    -   and optionally in the presence of    -   b) a nitrogen-, oxygen- and/or phosphorus-containing additive in        a catalytic or stoichiometric amount, based on the compound of        the general formula (II).

The organomagnesium compound (III) can be prepared in a manner familiarto the person skilled in the art, for example by Grignard reaction ofthe compound (II) with elemental magnesium, and under suitableconditions also by halogen-metal exchange or deprotonation, optionallywith addition of auxiliaries, for example lithium chloride, or bytransmetalation of other organometallic compounds, e.g. organolithiumcompounds, with suitable magnesium compounds, e.g. magnesium salts orGrignard compounds. It is particularly advantageous to perform thepreparation of the compound (III) by Grignard reaction in the presenceof an iron compound which is capable of catalyzing both this reactionand the coupling of (III) with (IV) (domino catalysis; cf. Jacobi vonWangelin et al., Angew. Chem. Int. Ed. 2009, 48, 607). In this case, itis also possible to allow both the reaction of (II) to give (III) andthe further reaction of (III) and (IV) to give (I) to proceed inparallel, i.e. to perform the preparation of (III) in the presence ofthe compound (IV), as a result of which the compound (III) formed insitu reacts immediately with compound (IV) to give the compound (I). Inthis case, it is possible to dispense with the isolation and/or storageof a potentially pyrophoric Grignard solution, which is thus difficultto handle under industrial conditions.

Examples of suitable organomagnesium compounds (III) are4-tolylmagnesium chloride, undecylmagnesium bromide,bis(4-tolyl)magnesium, bis(4-methoxyphenyl)magnesium-lithium chloridecomplex, 2-methoxyphenylmagnesium chloride-lithium chloride complex,lithium tributylmagnesate, lithium dibutyl-(3-tolyl)magnesate or lithiumtris(thiophen-2-yl)magnesate.

The R radical in the formulae (I), (II) and (III) is an optionallysubstituted (C₁-C₁₀)-alkyl, (C₂-C₁₀)-alkenyl, (C₆-C₂₄)-aryl radical orheteroaryl radical, where the heteroaromatic radical is a five-, six- orseven-membered ring having one or more nitrogen, phosphorus, oxygen orsulfur atoms in the ring. Aromatic, heteroaromatic and/or cycloaliphaticrings may optionally be fused onto cyclic radicals.

Examples of preferred aromatic R radicals are optionally mono- orpolysubstituted phenyl, naphthyl, anthracenyl or phenanthryl radicals.Examples of preferred heteroaromatic radicals are optionally mono- orpolysubstituted pyridyl, pyrimidyl, pyrazinyl, furyl, thiophenyl,oxazolyl, thiazolyl or pyrrolyl radicals. Preferred alkenylic radicalsare optionally mono- or polysubstituted vinyl radicals. Preferredalkylic radicals are optionally mono- or polysubstituted open-chain,cyclic, straight-chain or branched alkyl radicals, especiallyC₁-C₂₅-alkyl radicals.

The alkenylic, alkylic, aromatic or heteroaromatic R radical mayoptionally bear one or more substituents which may each independently be(C₁-C₁₈)-alkyl, (C₆-C₁₈)-cycloalkyl, (C₃-C₁₈)-alkenyl,(C₄-C₁₈)-cycloalkenyl, (C₄-C₁₈)-alkynyl, (C₄-C₁₈)-aryl,O—[(C₄-C₁₈)-alkyl], O—[(C₄-C₁₈)-aryl],O—Si[(C₄-C₁₈)-alkyl]_(n)[(C₄-C₁₈)-aryl]_(3-n), OC(O)—[(C₄-C₁₈)-alkyl],OC(O)—[(C₄-C₁₈)-aryl], NH₂, NH[(C₄-C₁₈)-alkyl], N[(C₄-C₁₈)-alkyl]₂,NH[(C₄-C₁₈)-aryl], N[(C₄-C₁₈)-aryl]₂, NHC(O)—[(C₄-C₁₈)-alkyl],N[(C₄-C₁₈)-alkyl]C(O)—[(C₄-C₁₈)-alkyl], NHC(O)—[(C₄-C₁₈)-aryl],N[(C₄-C₁₈)-alkyl]C(O)—[(C₄-C₁₈)-aryl], NO₂, NO, S—[(C₄-C₁₈)-aryl],S—[(C₄-C₁₈)-alkyl], fluorine, chlorine, bromine, CF₃, CN, COOM,COO—[(C₄-C₁₈)-alkyl], COO—[(C₄-C₁₈)-aryl], C(O)NH—[(C₄-C₁₈)-alkyl],C(O)NH—[(C₄-C₁₈)-aryl], C(O)N—[(C₄-C₁₈)-alkyl]₂, C(O)N—[(C₄-C₁₈)-aryl]₂,CHO, SO₂—[(C₄-C₁₈)-alkyl], SO—[(C₄-C₁₈)-alkyl], SO₂—[(C₄-C₁₈)-aryl],SO—[(C₄-C₁₈)-aryl], OSO₂—[(C₄-C₁₈)-alkyl], OSO₂—[(C₄-C₁₈)-aryl],PO—[(C₄-C₁₈)-alkyl]₂, PO—[(C₄-C₁₈)-aryl]₂, SO₃M, SO₃—[(C₄-C₁₈)-alkyl],SO₃—[(C₄-C₁₈)-aryl] or Si[(C₄-C₁₈)-alkyl]_(n)[(C₄-C₁₈)-aryl]_(3-n),where M is an alkali metal or alkaline earth metal atom and n is anatural number in the range from 0 to 3. In addition, two or more ofthese substituents may be joined to one another to form rings or ringsystems.

Examples of preferred aromatic R radicals are 2-tolyl, 4-anisyl,2-naphthyl, 4,4′-biphenyl, 3-tert-butoxycarbonylphenyl,3,4-(2,2-difluoromethylenedioxy)phenyl, pentafluorophenyl or 2-decalinylradicals. Examples of preferred heteroaromatic R radicals are4-trifluoromethylpyridyl, 4-quinolinyl, 3-methoxythiophen-2-yl,4-(2,2-ethylenedioxy)methylfuryl radicals. Examples of preferred vinylicR radicals are 2-methylprop-1-enyl, □-styryl, cyclohex-1-enyl,2-chlorobut-1-enyl, 3-squalenyl or but-2-en-2-yl radicals. Examples ofalkyl radicals are isopropyl, 1-butyl, 2-butyl, cyclohexyl,4-methoxycyclohexyl or perfluorobutyl radicals.

The allylic or vinylic R′ radical in formula (I) and formula (IV) mayoptionally bear one or more substituents Q which may each independentlybe (C₄-C₁₈)-alkyl, (C₄-C₁₈)-cycloalkyl, (C₄-C₁₈)-alkenyl,(C₄-C₁₈)-cycloalkenyl, (C₄-C₁₈)-alkynyl, (C₄-C₁₈)-aryl,O—[(C₄-C₁₈)-alkyl], O—[(C₄-C₁₈)-aryl],O—Si[(C₄-C₁₈)-alkyl]_(n)[(C₄-C₁₈)-aryl]_(3-n), OC(O)—[(C₄-C₁₈)-alkyl],OC(O)—[(C₄-C₁₈)-aryl], NH₂, NH[(C₄-C₁₈)-alkyl], N[(C₄-C₁₈)-alkyl]₂,NH[(C₄-C₁₈)-aryl], N[(C₄-C₁₈)-aryl]₂, NHC(O)—[(C₄-C₁₈)-alkyl],N[(C₄-C₁₈)-alkyl]C(O)—[(C₄-C₁₈)-alkyl], NHC(O)—[(C₄-C₁₈)-aryl],N[(C₄-C₁₈)-alkyl]C(O)—[(C₄-C₁₈)-aryl], NO₂, NO, S—[(C₄-C₁₈)-aryl],S—[(C₄-C₁₈)-alkyl], fluorine, chlorine, bromine, CF₃, CN, COOM,COO—[(C₄-C₁₈)-alkyl], COO—[(C₄-C₁₈)-aryl], C(O)NH—[(C₄-C₁₈)-alkyl],C(O)NH—[(C₄-C₁₈)-aryl], C(O)N—[(C₄-C₁₈)-alkyl]₂, C(O)N—[(C₄-C₁₈)-aryl]₂,CHO, SO₂—[(C₄-C₁₈)-alkyl], SO—[(C₄-C₁₈)-alkyl], SO₂—[(C₄-C₁₈)-aryl],SO—[(C₄-C₁₈)-aryl], OSO₂—[(C₄-C₁₈)-alkyl], OSO₂—[(C₄-C₁₈)-aryl],PO—[(C₄-C₁₈)-alkyl]₂, PO—[(C₄-C₁₈)-aryl]₂, SO₃M, SO₃—[(C₄-C₁₈)-alkyl],SO₃—[(C₄-C₁₈)-aryl] or Si[(C₄-C₁₈)-alkyl]_(n)[(C₄-C₁₈)-aryl]_(3-n),where M is an alkali metal or alkaline earth metal atom and n is anatural number in the range from 0 to 3. In addition, two or more ofthese substituents may be joined to one another to form rings or ringsystems.

Examples of preferred allylic R′ radicals are linear, branched andcyclic, optionally substituted (C₃-C₁₈)-1-alken-3-yls from the group ofallyl, crotyl, methallyl, 1-methylallyl, cyclopent-1-en-3-yl andcyclohex-1-en-3-yl. Examples of preferred vinylic R′ radicals arelinear, branched and cyclic, optionally substituted(C₃-C₁₈)-1-alken-1-yls from the group of vinyl, 1-propenyl,2-methyl-1-propenyl, cyclopent-1-en-1-yl or cyclohex-1-en-1-yl.

Typically, the process is performed by reacting the halogen compounds ofthe formula (II) with magnesium turnings to give the Grignard compound,then adding the catalytic amount of an iron or cobalt compound and thenslowly adding the allyl or vinyl compound of the formula (IV) dropwiseand then continuing to stir the reaction mixture for a period of 2 to 4hours. The purification of the product formed pursues typically bycolumn chromatography on silica gel.

If the compound of the formula (IV) is allyl acetate, the reaction iseffected with compounds of the formula (II) preferably from the group of4-bromoanisole, bromobenzene, 4-bromoveratrole, 4-bromotoluene,4-bromoanisole, 2-bromotoluene and 4-tert-butylbromobenzene.

Crotyl acetate as the compound of the formula (IV) can preferably bereacted with compounds of the formula (II) from the group of4-bromoanisole and 1-bromo-4-tert-butylbenzene.

If the compound of the formula (IV) is 3-vinylallyl acetate, thereaction is preferably effected with compounds of the formula (II) fromthe group of 1-bromo-4-chlorobenzene, 1-bromo-4-fluorobenzene,1-bromo-2,4-difluorobenzene, 2-bromoanisole, methyl 4-bromobenzoate,4-bromoanisole, 1,3-dibromobenzene, 1,4-dibromine, 4-bromoveratrole,4-bromoanisole, 4-bromotoluene, 4-tert-butylbromobenzene.

The R″ radical in formula (IV) may optionally bear one or moresubstituents which may each independently be (C₁-C₁₈)-alkyl,(C₁-C₁₈)-cycloalkyl, (C₁-C₁₈)-alkenyl, (C₁-C₁₈)-cycloalkenyl,(C₁-C₁₈)-alkynyl, (C₁-C₁₈)-aryl, O—[(C₁-C₁₈)-alkyl], O—[(C₁-C₁₈)-aryl],O—Si[(C₁-C₁₈)-alkyl]_(n)[(C₁-C₁₈)-aryl]_(3-n), OC(O)—[(C₁-C₁₈)-alkyl],OC(O)—[(C₁-C₁₈)-aryl], NH₂, NH[(C₁-C₁₈)-alkyl], N[(C₁-C₁₈)-alkyl]₂,NH[(C₁-C₁₈)-aryl], N[(C₁-C₁₈)-aryl]₂, NHC(O)—[(C₁-C₁₈)-alkyl],N[(C₁-C₁₈)-alkyl]C(O)—[(C₁-C₁₈)-alkyl], NHC(O)—[(C₁-C₁₈)-aryl],N[(C₁-C₁₈)-alkyl]C(O)—[(C₁-C₁₈)-aryl], NO₂, NO, S—[(C₁-C₁₈)-aryl],S—[(C₁-C₁₈)-alkyl], fluorine, chlorine, bromine, CF₃, CN, COOM,COO—[(C₁-C₁₈)-alkyl], COO—[(C₁-C₁₈)-aryl], C(O)NH—[(C₁-C₁₈)-alkyl],C(O)NH—[(C₁-C₁₈)-aryl], C(O)N—[(C₁-C₁₈)-alkyl]₂, C(O)N—[(C₁-C₁₈)-aryl]₂,CHO, SO₂—[(C₁-C₁₈)-alkyl], SO—[(C₁-C₁₈)-alkyl], SO₂—[(C₁-C₁₈)-aryl],SO—[(C₁-C₁₈)-aryl], OSO₂—[(C₁-C₁₈)-alkyl], OSO₂—[(C₁-C₁₈)-aryl],PO—[C₁-C₁₈)-alkyl]₂, PO—[(C₁-C₁₈)-aryl]₂, SO₃M, SO₃—[(C₁-C₁₈)-alkyl],SO₃—[(C₁-C₁₈)-aryl] or Si[(C₁-C₁₈)-alkyl]_(n)[(C₁-C₁₈)-aryl]_(3-n),where M is an alkali metal or alkaline earth metal atom and n is anatural number in the range from 0 to 3. In addition, two or more ofthese substituents may be joined to one another to form rings or ringsystems.

Examples of the R″ radical in formula (IV) are methyl, ethyl, propyl,isopropyl or phenyl, methoxy, ethoxy, propoxy, isopropoxy or phenoxyradicals.

Examples of compound (IV) are allyl acetate, crotyl propionate,methallyl dodecanoate, cyclohex-1-en-3-yl butanoate, allyl methylcarbonate, (hex-1-en-3-yl)phenyl carbonate, and also vinyl acetate,1-propenyl acetate, 2-propenyl methyl carbonate, cyclohex-1-en-1-ylpropionate.

The catalysts used are preferably transition metal compounds of groupVIIIB of the Periodic Table. Particular preference is given to usingiron or cobalt compounds, very particular preference being given tousing iron compounds in any oxidation state, preferably the +2 and +3oxidation states, for example iron(II) chloride, iron(III) chloride,iron(II) acetylacetonate, iron(II) acetylacetonate, iron(II) acetate,iron(III) acetate, iron(II) bromide, iron(III) bromide, iron(II)fluoride, iron(III) fluoride, iron(II) iodide, iron(III) iodide,iron(II) sulfate, iron(II) trifluoroacetate, iron(II)trifluoromethanesulfonate, iron(III) trifluoromethanesulfonate,iron(III) chloride-TMEDA complex.

The amount of catalyst used is preferably 0.01 to 100 mol %, morepreferably 0.1 to 10 mol %, based on the compound of the general formula(II).

It is optionally possible in the process according to the invention toadd nitrogen-, oxygen- and/or phosphorus-containing additives.

These additives are preferably alkylamines, cycloalkylamines,alkyldiamines, cycloalkyldiamines, N-containing heterocycles,alkylamides, cyclic alkylamides, alkylimines, aniline derivatives,ureas, urethanes, nitrogen-containing heteroaromatics, dialkyl ethers,alkyl aryl ethers, diaryl ethers, cyclic ethers, oligoethers,polyethers, triarylphosphines, trialkylphosphines,aryldialkylphosphines, alkyldiarylphosphines and bridged bisphosphines.

The additives used are more preferably triethylamine,ethyldiisopropylamine, N,N,N′,N′-tetramethylethylenediamine (TMEDA),1,4-diazabicyclo[2.2.2]octane (DABCO), sparteine,N,N,N′,N′-tetramethyldiaminomethane, 1,2-diaminocyclohexane (DACH),N-methyl-2-pyrrolidine (NMP), N,N-dimethylaniline, pyridine,phenanthroline, PEG (polyethylene glycol), DME (1,2-dimethoxyethane),binaphthyl dimethyl ether, 18-crown-6, triphenylphosphine,tri-n-butylphosphine, tri-tert-butylphosphine, dppf(1,1′-bis(diphenylphosphino)ferrocene), dppe(1,2-bis(diphenylphosphino)ethane), dppp(1,3-bis(diphenylphosphino)propane), dppb(1,4-bis(diphenylphosphino)butane) or dpppe(1,5-bis(diphenylphosphino)pentane).

It is also possible to use chiral additives in order to achieve chiralinduction in the coupling reaction, if applicable.

In the process according to the invention, the nitrogen-, oxygen- and/orphosphorus-containing additive is used preferably in an amount of 0 to200 mol %, more preferably 0 to 150 mol %, based on the compounds (II).

The process according to the invention is typically performed in dryaprotic polar solvents, which are preferably used in dry form.Particular preference is given to using tetrahydrofuran (THF),2-methyltetrahydrofuran (2-methyl-THF), 1,4-dioxane, dimethylformamide(DMF), dimethylacetamide (DMAc), methyl tert-butyl ether (MTBE), diethylether, 1,2-dimethoxyethane (DME, glyme), diisopropyl ether (DIPE),dipropyl ether, dibutyl ether, cyclopentyl methyl ether, diethyleneglycol dimethyl ether (diglyme), triethylene glycol dimethyl ether(triglyme), tetraethylene glycol dimethyl ether (tetraglyme), diethyleneglycol dibutyl ether, dimethyl carbonate or N-methyl-2-pyrrolidone (NMP)as the solvent.

The reaction temperature in the process according to the invention istypically between −80° C. and +100° C., preferably between −40 and +60°C., more preferably between −15 and +45° C.

In the process according to the invention, it is possible to react amultitude of substituted and unsubstituted aryl, heteroaryl, alkyl andalkenyl halides with substituted and unsubstituted allyl and vinylesters of substituted and unsubstituted carboxylic acids and carbonicacid. The coupling is effected in most cases predominantly at the carbonatom of the allyl or vinyl ester that bears the ester function, whichmeans that isomerization and allyl shifts take place only to a minordegree, if at all.

The compounds prepared by the process according to the invention can beisolated and purified efficiently by conventional methods.

EXAMPLES Example 1 Coupling of Allyl Acetate with2-methoxyphenylmagnesium Bromide

Under protective gas, 63 mg of magnesium turnings, 126 mg of anhydrouslithium chloride, 4 ml of dry tetrahydrofuran and 2.4 mmol of2-bromoanisole were reacted at room temperature to give the Grignardcompound. Then the dark-colored solution formed was cooled to 0° C. anda solution of 35.3 mg of iron(III) acetylacetonate (5 mol %) in 2 ml ofdry tetrahydrofuran was added and the mixture was stirred for fiveminutes. Then 2 mmol of allyl acetate were added dropwise and thereaction mixture was stirred for 2 h. For workup, hydrolysis waseffected with 5 ml of saturated sodium hydrogencarbonate solution andthe mixture was extracted three times with 10 ml each time of ethylacetate. The combined organic phases were dried over magnesium sulfate,concentrated and purified by column chromatography on silica gel(eluent: cyclohexane-ethyl acetate). 95% of theory of 2-allylanisole wasisolated.

Examples 2 to 17 Further Couplings of Aryl Grignard Compounds with AllylAcetate

The procedure was as in example 1, except that the haloarenes listed intable 1 were used instead of 2-bromoanisole. The individual yields arenot optimized.

TABLE 1 Exam- Yield ple (% of No. Haloaromatic Product theory) 24-bromoanisole 4-allylanisole 75 3 bromobenzene allylbenzene 70 44-bromoveratrole 4-allylveratrole 72 5 4-bromotoluene 4-allyltoluene 756 1,3-dibromobenzene 4-allylbromobenzene 71 7 4-bromo-N,N- 4-allyl-N,N-61 dimethylaniline dimethylaniline 8 2-bromo-N,N- 2-allyl-N,N- 31dimethylaniline dimethylaniline 9 2-bromotoluene 2-allyltoluene 69 104-bromo-tert-butylbenzene 4-allyl-tert-butylbenzene 54 114-bromo-2-fluorobiphenyl 4-allyl-2-fluorobiphenyl 60 129-bromophenanthrene 9-allylphenanthrene 76 13 1,4-dibromobenzene4-allylbromobenzene 35 14 2-bromobenzonitrile 2-allylbenzonitrile 15 151-bromo-4-fluorobenzene 4-allylfluorobenzene 75 164-bromobenzotrifluoride 4-allylbenzotrifluoride 51 17 5-bromo-m-xylene5-allyl-m-xylene 63

Example 18 Coupling of an Alkyl Grignard Compound with Allyl Acetate

n-dodecyl bromide was converted analogously to example 1 to its Grignardcompound and the latter was reacted with allyl acetate in the mannerdescribed. 1-Pentadecene was obtained in 32% yield.

Examples 19 to 23 Coupling of Aryl Grignard Compounds with AllylCarbonate

The experiments were conducted analogously to example 1; instead ofallyl acetate, allyl methyl carbonate was used. The experiments arelisted in table 2. The individual yields are not optimized.

TABLE 2 Exam- Yield ple (% of No. Haloarene Product theory) 194-bromotoluene 4-allyltoluene 50 20 2-bromoanisole 2-allylanisole 76 214-bromoanisole 4-allylanisole 68 22 2-bromotoluene 2-allyltoluene 56 234-tert-butylbromobenzene 4-allyl-tert-butylbenzene 50

Examples 24 to 37 Coupling of Aryl Grignard Compounds with SubstitutedAllyl Acetates

The experiments were conducted analogously to example 1; instead ofallyl acetate, the substituted allyl acetates listed in table 3 werereacted with the aryl Grignard compounds listed. The individual yieldswere not optimized.

TABLE 3 Yield No. Allyl compound Haloarene Product (%) 24 crotyl acetate4-bromoanisole 4-crotylanisole   30^(a)) 25 crotyl acetate1-bromo-4-tert- 1-tert-butyl-4-   22^(a)) butylbenzene crotylbenzene 263-phenylallyl acetate 1-bromo-4- 4-(3- 94 chlorobenzenephenylallyl)chlorobenzene 27 3-phenylallyl acetate 1-bromo-4- 4-(3- 95fluorobenzene phenylallyl)fluorobenzene 28 3-phenylallyl acetate1-bromo-2,4- 4-(3-phenylallyl)-m- 49 difluorobenzene difluorobenzene 293-phenylallyl acetate 2-bromoanisole 2-allylanisole 51 30 3-phenylallylacetate methyl 4- methyl 4-(3- 16 bromobenzoate phenylallyl)benzoate 313-phenylallyl acetate 4-bromoanisole 4-(3-phenylallyl)anisole 62 323-phenylallyl acetate 1,3-dibromobenzene 3-(3- 21phenylallyl)bromobenzene 33 3-phenylallyl acetate 1,4-dibromobenzene4-(3- 52 phenylallyl)bromobenzene 34 3-phenylallyl acetate4-bromoveratrole 4-(3-phenylallyl)veratrole 54 35 prenyl acetate4-bromoanisole 4-prenylanisole   37^(a)) 36 prenyl acetate4-bromotoluene 4-prenyltoluene   35^(a)) 37 methyl 3-acetoxy-2- 4-tert-methyl 2-(4-tert-   41^(a)) methylenebutanoate butylbromobenzenebutylbenzylidene)butanoate (^(a))isomer mixture)

Examples 38 to 40 Variation of the Coupling Temperature of the AllylAcetate Coupling

Allyl acetate and 4-tert-butylphenylmagnesium bromide were reacted asdescribed in example 10, except that the coupling reaction was conductedat the temperature listed in table 4.

TABLE 4 No. Temperature (° C.) Yield (%) 38 20 31 39 0 37 40 −20 34

Examples 41 to 43 Variation of the Catalyst in the Allyl AcetateCoupling

Allyl acetate and 4-tert-butylphenylmagnesium bromide were reacted asdescribed in example 10, except that the coupling reaction was conductedwith the catalyst specified in table 5 (5 mol %).

TABLE 5 No. Catalyst Yield (%) 41 iron(III) chloride 37 42 iron(III)acetylacetonate 37 43 iron(II) iodide 7

Examples 44 to 47 Variation of the Stoichiometry in the Allyl AcetateCoupling

Allyl acetate and 4-tert-butylphenylmagnesium bromide were reacted asdescribed in example 10, except that the stoichiometric ratios werevaried as described in table 6.

TABLE 6 Molar bromoarene:allyl No. acetate ratio Yield (%) 44 1.0:1.2 3345 1.0:1.5 37 46 1.2:1.0 40 47 1.5:1.0 51

Examples 48 to 52 Variation of Additives in the Allyl Acetate Coupling

Allyl acetate and 4-tert-butylphenylmagnesium bromide were reacted asdescribed in example 10, except that the additives listed in table 7were added in the amounts specified in each case.

TABLE 7 Eq. of Eq. of No. LiCl TMEDA Yield (%) 48 1.5 0.0 47 49 1.5 0.444 50 1.5 0.9 39 51 1.5 1.5 37 52 0.0 0.0 37

Examples 53 Coupling of 4-tolylmagnesium Bromide with Vinyl Acetate

Under protective gas, 96 mg of magnesium turnings were initially chargedunder 6 ml of a 0.5 M solution of lithium chloride in tetrahydrofuran.At 20° C., 2.6 mmol of 4-bromotoluene were added and the mixture wasstirred for 2 h. A solution of 16.2 mg of iron(III) chloride (5 mol %)and 292 μl of TMEDA (1.3 eq.) in 1 ml of tetrahydrofuran was added tothe Grignard solution formed. Then the mixture was cooled to 0° C. and 2mmol of vinyl acetate were added, and the mixture was stirred at 0° C.for 3 h and at 20° C. for 1 h. For workup, 4 ml of saturated sodiumcarbonate solution were added and the mixture was extracted three timeswith 5 ml each time of ethyl acetate. The combined organic extracts weredried over sodium sulfate and purified by column chromatography onsilica gel (eluent: cyclohexane-ethyl acetate).

This gave 4-methylstyrene in a yield of 99% of theory.

Example 54 Coupling of 4-bromoanisole with Vinyl Acetate

The reaction was conducted analogously to example 53, except using4-bromoanisole instead of 4-bromotoluene. This gave 4-methoxystyrene in100% yield.

Example 55 Coupling of Bromotoluene with Vinyl Acetate as Under DominoIron Catalysis

Under protective gas, 62 mg of magnesium turnings were initially chargedunder a solution of 16.2 mg (5 mol %) of iron(III) chloride in 6 ml ofabs. tetrahydrofuran, and 60 t1 of TMEDA (20 mol %) were added. Themixture was cooled to 0° C. and stirred for another 10 mm, then 2.6 mmolof bromobenzene were added and the mixture was stirred at 0° C. for 90mm, then 2 mmol of vinyl acetate were added and the mixture was stirredonce again at 0° C. for 90 min. For workup, 2 ml of saturated sodiumcarbonate solution were added to the reaction mixture, which wasextracted three times with 5 ml each time of ethyl acetate. The combinedorganic phases were dried over sodium sulfate, concentrated and purifiedby column chromatography on silica gel (eluent: cyclohexane-ethylacetate).

This gave styrene in a yield of 42% of theory.

What is claimed is:
 1. A process for preparing organic compounds of thegeneral formula (I)R—R′  (I) in which R is an optionally mono- or polysubstituted aryl,heteroaryl, alkenyl or alkyl radical, and R′ is an optionallysubstituted vinyl radical or ally radical, and the process comprises:converting a compound of the general formula (II)R—X  (II) in which X is fluorine, chlorine, bromine or iodine, and R isas defined for formula (I), to an organomagnesium compound of thegeneral formula (III)[M⁺]_(n)[R_(m)MgX_(k)Y_(l)]  (III) in which R is as defined for formula(I), X is an anion as defined for formula (II), M is a monovalentcation, Y is a monovalent anion, n is either 0 or n is 1, 2, 3, 4, m is1, 2, 3, 4, 5 or 6, k is 0, 1, 2, 3 or 4, l is 0, 1, 2, 3 or 4, andn+2=m+k+l, and reacting the organomagnesium compound (III) with acompound of the general formula (IV)

in which R′ is as defined for formula (I) and is bonded to the oxygenatom in the allyl or vinyl position, and R″ is an optionally substitutedalkyl, alkoxy, aryl, aryloxy, heteroaryl or heteroaryloxy group, toproduce the compound of the general formula (I); wherein the processcomprises converting compound (II) to compound (III) in the presence ofa) catalytic amounts of an iron compound, based on the compound of thegeneral formula (II), b) the compound of general formula (IV), andoptionally c) a nitrogen-, oxygen- and/or phosphorus-containing additivein a catalytic or stoichiometric amount, based on the compound of thegeneral formula (II); wherein, after formation of the organomagnesiumcompound (III), the organomagnesium compound (III) reacts further insitu with the compound of the general formula (IV) to produce thecompound of the general formula (I).
 2. The process according to claim1, wherein R is an optionally substituted alkenyl, alkyl, aryl orheteroaryl radical, where the heteroaryl radical is a five-, six- orseven-membered ring having one or more nitrogen, oxygen and/or sulfuratoms in the ring, where any further optionally substituted aromatic,heteroaromatic and/or cycloaliphatic radicals may be fused onto a cyclicR radical and the R radical may optionally bear one or more substituentswhich may each independently be (C₃-C₁₈)-alkyl, (C₃-C₁₈)-cycloalkyl,(C₃-C₁₈)-alkenyl, (C₃-C₁₈)-cycloalkenyl, (C₃-C₁₈)-alkynyl,(C₆-C₁₈)-aryl, O—[(C₄-C₁₈)-alkyl], O—[(C₆-C₁₈)-aryl],O—Si[(C₄-C₁₈)-alkyl]_(n)[(C₄-C₁₈)-aryl]_(3-n), OC(O)—[(C₄-C₁₈)-alkyl],OC(O)—[(C₄-C₁₈)-aryl], NH₂, NH[(C₄-C₁₈)-alkyl], N[(C₄-C₁₈)-alkyl]₂,NH[(C₄-C₁₈)-aryl], N[(C₄-C₁₈)-aryl], NHC(O)—[(C₄-C₁₈)-alkyl],N[(C₄-C₁₈)-alkyl]C(O)—[(C₄-C₁₈)-alkyl], NHC(O)—[(C₄-C₁₈)-aryl],N[(C₄-C₁₈)-alkyl]C(O)—[(C₄-C₁₈)-aryl], NO₂, NO, S—[(C₄-C₁₈)-aryl],S—[(C₄-C₁₈)-alkyl], fluorine, chlorine, bromine, pentafluorosulfuranyl,CF₃, CN, COOM, COO [(C₄-C₁₈)-alkyl], COO—[(C₄-C₁₈)-aryl],C(O)NH—[(C₄-C₁₈)-alkyl], C(O)NH—[(C₄-C₁₈)-aryl],C(O)N—[(C₄-C₁₈)-alkyl]₂, C(O)N—[(C₄-C₁₈)-aryl]₂, CHO,SO₂—[(C₄-C₁₈)-alkyl], SO—[(C₄-C₁₈)-alkyl], SO₂—[(C₄-C₁₈)-aryl],SO—[(C₄-C₁₈)-aryl], OSO₂—[(C₄-C₁₈)-alkyl], OSO₂—[(C₄-C₁₈)-aryl],PO—[(C₄-C₁₈)-alkyl]₂, PO—[(C₄-C₁₈)-aryl]₂, SO₃M, SO₃—[(C₄-C₁₈)-alkyl],SO₃—[(C₄-C₁₈)-aryl] or Si[C₄-C₁₈)-alkyl]_(n)[(C₄-C₁₈)-aryl]_(3-n), whereM is an alkali metal or alkaline earth metal atom and n is a naturalnumber in the range from 0 to 3, and where at least two of thesesubstituents may form a ring system with one another.
 3. The processaccording to claim 1, wherein the one or more substituents Q may eachindependently be (C₄-C₁₈)-alkyl, (C₄-C₁₈)-cycloalkyl, (C₄-C₁₈)-alkenyl,(C₄-C₁₈)-cycloalkenyl, (C₄-C₁₈)-alkynyl, (C₄-C₁₈)-aryl,O—[(C₄-C₁₈)-alkyl], O—[(C₄-C₁₈)-aryl],O—Si[(C₄-C₁₈)-alkyl]_(n)[(C₄-C₁₈)-aryl]_(3-n), OC(O)—[(C₄-C₁₈)-alkyl],OC(O)—[(C₄-C₁₈)-aryl], NH₂, NH[(C₄-C₁₈)-alkyl], N[(C₄-C₁₈)-alkyl]₂,NH[(C₄-C₁₈)-aryl], N[(C₄-C₁₈)-aryl]₂, NHC(O)—[(C₄-C₁₈)-alkyl],N[(C₄-C₁₈)-alkyl]C(O)—[(C₄-C₁₈)-alkyl], NHC(O)—[(C₄-C₁₈)-aryl],N[(C₄-C₁₈)-alkyl]C(O)—[(C₄-C₁₈)-aryl], NO₂, NO, S—[(C₄-C₁₈)-aryl],S—[(C₄-C₁₈)-alkyl], fluorine, chlorine, bromine, pentafluorosulfuranyl,CF₃, CN, COOM, COO—[(C₄-C₁₈)-alkyl], COO—[(C₄-C₁₈)-aryl],C(O)NH—[(C₄-C₁₈)-alkyl], C(O)NH—[(C₄-C₁₈)-aryl],C(O)N—[(C₄-C₁₈)-alkyl]₂, C(O)N—[(C₄-C₁₈)-aryl]₂, CHO,SO₂—[(C₄-C₁₈)-alkyl], SO—[(C₄-C₁₈)-alkyl], SO₂—[(C₄-C₁₈)-aryl],SO—[(C₄-C₁₈)-aryl], OSO₂—[(C₄-C₁₈)-alkyl], OSO₂—[(C₄-C₁₈)-aryl],PO—[(C₄-C₁₈)-alkyl]₂, PO—[(C₄-C₁₈)-aryl]₂, SO₃M, SO₃—[(C₄-C₁₈)-alkyl],SO₃—[(C₄-C₁₈)-aryl] or Si[(C₄-C₁₈)-alkyl]_(n)[(C₄-C₁₈)-aryl]_(3-n),where M is an alkali metal or alkaline earth metal atom and n is anatural number in the range from 0 to 3, and where at least two of thesesubstituents may form a ring system with one another.
 4. The processaccording to claim 1 wherein the R″ radical is an optionally branched,optionally cyclic alkyl group or an aryl or heteroaryl group, all ofwhich may optionally bear one or more substituents which may eachindependently be (C₁-C₁₈)-alkyl, (C₄-C₁₈)-cycloalkyl, (C₄-C₁₈)-alkenyl,(C₄-C₁₈)-cycloalkenyl, (C₄-C₁₈)-alkynyl, (C₄-C₁₈)-aryl,O—[(C₄-C₁₈)-alkyl], O—[(C₄-C₁₈)-aryl],O—Si[(C₄-C₁₈)-alkyl]_(n)[(C₄-C₁₈)-aryl]_(3-n), OC(O)—[(C₄-C₁₈)-alkyl],OC(O)—[(C₄-C₁₈)-aryl], NH₂, NH[(C₄-C₁₈)-alkyl], N[(C₄-C₁₈)-alkyl]₂,NH[(C₄-C₁₈)-aryl], N[(C₄-C₁₈)-aryl]₂, NHC(O)—[(C₄-C₁₈)-alkyl],N[(C₄-C₁₈)-alkyl]C(O)—[(C₄-C₁₈)-alkyl], NHC(O)—[(C₄-C₁₈)-aryl],N[(C₄-C₁₈)-alkyl]C(O)—[(C₄-C₁₈)-aryl], NO₂, NO, S—[(C₄-C₁₈)-aryl],S—[(C₄-C₁₈)-alkyl], fluorine, chlorine, bromine, pentafluorosulfuranyl,CF₃, CN, COOM, COO—[(C₄-C₁₈)-alkyl], COO—[(C₄-C₁₈)-aryl],C(O)NH—[(C₄-C₁₈)-alkyl], C(O)NH—[(C₄-C₁₈)-aryl],C(O)N—[(C₄-C₁₈)-alkyl]₂, C(O)N—[(C₄-C₁₈)-aryl]₂, CHO,SO₂—[(C₄-C₁₈)-alkyl], SO—[(C₄-C₁₈)-alkyl], SO₂—[(C₄-C₁₈)-aryl],SO—[(C₄-C₁₈)-aryl], OSO₂—[(C₄-C₁₈)-alkyl], OSO₂—[(C₄-C₁₈)-aryl],PO—[(C₄-C₁₈)-alkyl]₂, PO—[(C₄-C₁₈)-aryl]₂, SO₃M, SO₃—[(C₄-C₁₈)-alkyl],SO₃—[(C₄-C₁₈)-aryl] or Si[(C₄-C₁₈)-alkyl]_(n)[(C₄-C₁₈)-aryl]_(3-n),where M is an alkali metal or alkaline earth metal atom and n is anatural number in the range from 0 to 3, and where at least two of thesesubstituents may form a ring system with one another.
 5. The processaccording to claim 1, wherein the iron compound is iron(II) chloride,iron(III) chloride, iron(II) acetylacetonate, iron(III) acetylacetonate,iron(II) acetate, iron(III) acetate, iron(II) bromide, iron(III)bromide, iron(II) fluoride, iron(III) fluoride, iron(II) iodide,iron(III) iodide, iron(II) sulfate, iron(II) trifluoroacetate, iron(II)trifluoromethanesulfonate, iron(III) trifluoromethanesulfonate oriron(III) chloride-TMEDA complex.
 6. The process according to claim 1,wherein the iron compound is used in an amount of 0.01 to 50 mol %,based on the compound of the general formula (II).
 7. The processaccording to claim 1, wherein the optionally added nitrogen-, oxygen-and/or phosphorus-containing additive having one or more nitrogen,oxygen and/or phosphorus atoms comprises optionally substitutedalkylamines, N-containing heterocycles, alkylamides, cyclic alkylamides,cycloalkylamines, cycloalkyldiamines, alkylimines, cycloalkylimines,aniline, aniline derivatives, nitrogen-containing heteroaromatics,dialkyl ethers, alkyl aryl ethers, diaryl ethers, cyclic ethers,oligoethers, polyethers, triarylphosphines, trialkylphosphines,aryldialkylphosphines, alkyldiarylphosphines and bridged bisphosphines.8. The according to claim 1, wherein the nitrogen-, oxygen- and/orphosphorus-containing additive used is triethylamine,ethyldiisopropylamine, N,N,N′,N′-tetramethylethylenediamine (TMEDA),1,4-diazabicyclo[2.2.2]octane (DABCO), sparteine,N,N,N′,N′-tetramethyldiaminomethane, diaminocyclohexane (DACH),N-methyl-2-pyrrolidine (NMP), N,N-dimethylaniline, pyridine,phenanthroline, PEG-DME (polyethylene glycol dimethyl ether), DME(1,2-dimethoxyethane), binaphthyl dimethyl ether, 18-crown-6,triphenylphosphine, tri-n-butylphosphine, tri-tert-butylphosphine, dppf(1,1′-bis(diphenylphosphino)ferrocene), dppe(1,2-bis(diphenylphosphino)ethane), dppp(1,3-bis(diphenylphosphino)propane), dppb(1,4-bis(diphenylphosphino)butane) or dpppe(1,5-bis(diphenylphosphino)pentane).
 9. The process according to claim1, wherein the nitrogen-, oxygen- and/or phosphorus-containing additiveis used in an amount of 0 to 200 mol %, based on the compound of thegeneral formula (II).
 10. The process according to claim 1, wherein: theR radical in formula (I) is an aryl radical from the group of phenyl,naphthyl, anthracenyl, or phenanthryl, or a heteroaryl radical from thegroup of pyridyl, pyrimidyl, pyrazinyl, dioxinyl, furyl, (thiophen)yl,oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, imidazolyl, pyrazolyl,oxadiazolyl, thiadiazolyl, triazolyl, or pyrrolyl, and the R′ radical informula (I) is an allylic radical from the group of allyl, crotyl,methallyl, 1-methylallyl, cyclopent-1-en-3-yl, or cyclohex-1-en-3-yl, ora vinylic radical from the group of vinyl, 1-propenyl,2-methyl-1-propenyl, cyclopent-1-en-1-yl, or cyclohex-1-en-1-yl.